Wednesday, August 24, 2011

Counting the Holes, Not the Trees

How do you count 50,000 trees? How do you count 3,000,000? Recently, I blogged about Richardson's "Tree the Town" program (goal: plant 50,000 trees) and North Texas's "Tree North Texas" program (goal: plant 3,000,000 trees) and pondered the challenge of counting all those trees.

Since then, I've learned a thing or two from readers (wonderful readers!) that turns my thinking completely upside down. I experienced an "ah ha!" moment. You know, when the light bulb clicks on over your head (the new cool squiggly kind, not the old Easy-Bake Oven heat source kind). I was thinking about the problem of counting trees in the exact opposite way I should have been. The experience reminded me of a chapter in the history of science:

"Around 1752, Benjamin Franklin developed his theory on the flow of electricity. Franklin believed that electricity flows like a fluid, and this fluid flows from areas of positive charge to areas of negative charge. It would be over 100 years before it was understood that current flow was actually the movement of charged particles.

"By the time science understood that electric current was the movement of negatively charged electrons, it was too late to change the standards, the textbooks, the schematic diagrams, and the generally accepted theory. The direction of current flow was set as opposite to the actual flow of the charge carriers, which we now know flow from areas of negative charge to areas of positive charge."
-- Everything2.com

Today, it's best to think of electric current not as a flow of electrons in one direction, but as a flow of "holes" left behind as electrons move in the opposite direction.

After the jump, why Ben Franklin's mistake is like the challenge of counting trees.

I was thinking of the challenge of projects like "Tree North Texas" as a problem of counting trees. At least to start with, when we're expending more effort planting trees than maintaining them, the problem is actually a problem of counting "holes." Where are we going to put all those trees?

"Texas Trees Foundation" has developed a mapping application to identify all potential tree planting sites in a city. They applied this to Dallas. The tool "identifies the potential sites for specific environmental purposes and then it quantifies the economic value of the trees over a 40 year period." Instead of just "plopping" trees down randomly, locations can be prioritized and strategically chosen for economic and environmental purposes.

I liken it to automatically scanning a Google Maps aerial image of the city and making note of the bare areas and categorizing them as paved areas, grassy areas, bare soil, water, power line easements, etc. The species of tree suitable for each area can be determined to guide the tree-planting program to return maximum benefits.

More details about the application can be found in "The Dallas GIS Roadmap Model For Urban Tree Planning & Planting." Stay with me. It's much more readable than its clunky title suggests. "Texas Trees Foundation" really needs a catchy name for this technology. They also need contributions to continue to develop it (for example, to make the interactive tool available to the public) and to deploy the technology to other cities (hint, Richardson). So, go ahead and click the link and read the report, then make a contribution to "Texas Trees Foundation." Your return will be improved air quality, less rain runoff and erosion, reduced energy consumption, and a more pleasant environment to live, work and play.